The present invention relates to calibration of handpieces that make cavities, and, more particularly for calibration of such handpieces that have a tip whose position is difficult to, or cannot be, calibrated by image-guided systems.
Image-guided navigation of surgical handpieces, such as dental handpieces, is well-known. For example, U.S. Pat. No. 7,457,443 to Persky describes a particular method of compensating for distortions generated in an imaging process, and comprises providing a registration device with a plurality of markers disposed in a predetermined three-dimensional pattern, the markers being rendered visible in the imaging process; producing a scanned image of an object of interest in the presence of the registration device; and correcting the data of said scanned image such that the image of the markers accurately reproduces the predetermined three-dimensional pattern. This image-guided navigation is typically used for dental handpieces that are used to drill teeth by means of the rotation of a shaft connected to a symmetrically shaped drill bit that causes cavitation.
The problem is that with the advent of new technologies for drilling bone, certain surgical handpieces, including dental handpieces, may have tips whose position cannot as a practical matter, or without great difficulty or cannot at all, be precisely defined or calibrated using known image-guided systems, for example because the tips of the handpieces have an irregular shape. Such handpieces may make holes, for example in bone, by means of other technologies rather than by ordinary drilling by rotation. For example, some handpieces induce cavitation by shooting high pressure steam through a tiny curved or twisted hose tip. As shown in FIG. 1, a handpiece for steam-based cavitation may shoot steam through a curved or irregularly shaped tip. In other cases, the handpieces cut bone using ultrasonic vibration or energy.
For handpieces using these other non-rotary drilling technologies, in which the tip of the handpiece may be shaped irregularly, or the end of the tip or the line of action of the handpiece is not along the longitudinal axis of the handpiece, calibration of the tip of the handpiece may be too difficult or impractical or even impossible using the known image-guided technologies. The shape of the tip may be too difficult or impossible to be precisely defined by the image-guided system. For the surgery by image-guided system to succeed, however, calibration of the tip of the handpiece is essential. It is well known that in dental and other surgeries, precision is an essential ingredient to a successful operation.
There is a compelling need for an apparatus, system and/or method of calibration for cavitation-inducing handpieces, the position of whose tip is impractical, too difficult or impossible to be defined by known image-guided systems, for example because the tip of the handpiece may have a curved or irregular shape.